devi, V. 2014. M (X)/G/1 WITH TWO PHASE OF HETEROGENEOUS SERVICE UNDER DIFFERENT VACATION POLICY , RESTRICTED ADMISSIBILITY AND SET UP. JOURNAL OF ADVANCES IN MATHEMATICS. 9, 5 (Dec. 2014), 2687–2695. DOI:https://doi.org/10.24297/jam.v9i5.2351.